The present invention relates to a drying means for removing excess moisture held by a wet sheet which has passed through a liquid developing section in a copying machine.
In prior art, drying means for removing excess moisture held by a wet sheet which has passed through a liquid developing section in a copying machine such as an electrophotographic duplicating apparatus and an electrostatic recording apparatus, a knife edge, wringing rollers, a suction fan or a blower has been used.
However, the above-mentioned knife edge, wringing rollers, suction fan or blower are not effective when they are used alone. An effective combination comprises a knife edge and a blower. However, a knife edge is not suited for a sheet having a plurality of holes formed therein, such as a sprocket driven sheet, because the knife edge will catch the hole formed in the sheet.
The suction fan is not suited as a drying means, because it is almost impossible to extract the excess moisture held by the wet sheet. Therefore, the blower is usually provided in addition to the suction fan.
The wringing rollers are most effective to dry the wet sheet. The wringing rollers are usually installed not only for removing the excess moisture held by the wet sheet but also for driving the sheet in a certain direction. The wringing rollers are installed in a fashion to traverse the wet sheet and to come into contact with the whole surface of the wet sheet. This will cause a meandering drive or an inclined drive of the sheet.
It has also been proposed to provide a rotatable drying roller adjacent to a photosensitive drum in a copying machine. In this example, the rotatable drying roller is installed apart from the surface of the photosensitive drum a distance of about 0.1 to 0.2 mm in order to protect the drum surface from being damaged. Therefore, the moisture will unavoidably remain on the drum surface with a thickness of 0.1 to 0.2 mm.